htmlCheckEncoding doesn't update input-end after shrink

* HTMLparser.c: add the missing update to the end pointer
diff --git a/HTMLparser.c b/HTMLparser.c
index 3d4831c..da3b173 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -3478,6 +3478,8 @@
 	    }
 	    ctxt->input->base =
 	    ctxt->input->cur = ctxt->input->buf->buffer->content;
+            ctxt->input->end =
+                          &ctxt->input->base[ctxt->input->buf->buffer->use];
 	}
     }
 }